Pump and signal combiner for bi-directional pumping of all-fiber lasers and amplifiers(6)

Pump and signal combiner for bi-directional pumping of all-fiber lasers and amplifiers(6)

4.4 Experimental results

In order to verify the simulations, two fiber combiners with a single pump port based on the setup described in Section 2 were developed. For the first combiner an IF with a low TR of 2.6 and a short TL of 9.5 mm was fabricated. In the case of the second combiner the TR and the TL were increased to 6.7 and 18 mm, respectively. For both combiners the geometrical dimensions of the obtained tapered IFs were measured with an optical microscope. After completion of the fabrication, both combiners were optically characterized. Therefore, each PFF (pump port) with a NA of 0.15 was connected to a pump diode (Oclaro BMU25) with a pigtail fiber delivering a maximum output power of ~25 W at a wavelength of 976 nm. The delivery fiber of the pump diode had parameters identical to the PFF.

The experimental results for the first fiber combiner are shown in Fig. 6(a)

Fig. 6 Coupled and transmitted power measured for a fiber combiner with one pump port with (a) a TL of 9.5 mm (TR of 2.6) and (b) a TL of 18 mm (TR 6.7), * ratio of coupled or transmitted power to total diode power in percent.

. Due to the low TR of 2.6, an experimental pump coupling efficiency of only 74% was achieved. The residual pump power was almost completely measured as TP, with a power fraction of 25.3%. The simulations for the coupled as well as the TP show good agreement with the experimental results, and confirm that in the case of a low TR of 2.6, the pump power is only divided into coupled power and TP. In Fig. 6(a) it can be seen that in the simulations the sum of the coupled and TP is 99.9%, corresponding to 0.1% of pump light rays not detected in the simulations. This can be treated as a simulation error. That the measured sum of coupled pump power and TP is only 99.3% can be explained by measurement uncertainties, marginal splice losses and additional power losses in the fiber component caused by dust particles. Since the thermal load of this fiber combiner design is negligible it would be feasible to couple several kW of pump power, but with the disadvantage of a moderate coupling efficiency of about 75% and consequently a undesirable overall efficiency for high power laser system.

For the second fiber combiner, depicted in Fig. 6(b), a higher pump coupling efficiency of 95.2% (96.0% in simulation) was measured as compared to the first combiner presented in Fig. 6(a) due to the increase in TR and TL. Following the simulations the residual pump power of 4% can be divided into TP, PCT and PAA with 2.4%, 0.6% and 0.9%, respectively. Again, the missing pump power of 0.1% was associated with an error owing to undetected power in the simulations. For the TP a fraction of 2.3% was measured and shows very good agreement with the simulation (2.4%), i.e. more than 50% of the total power loss was TP. This fraction of power represents no risk for damage to the fiber component. Due to the excellent agreement between simulation and experiment, the simulated PCT-fraction of only 0.6% is a good value for an estimate of the thermal load of the coating of the TF. Based on the simulations and experiments an error of less than 1% of the pump input power can be assumed for the PCT-fraction.

Unfortunately, the power fractions PAA and PCT are difficult to measure and therefore could not be experimentally determined. In future work an indirect measurement of PCT will be realized by measuring the coating temperature of the CWDM Module. In summary, the simulations describe the coupling efficiency as well as the fraction of TP very well, and thus, serve as a very good estimation for the fraction of PCT and PAA.

 

DK Photonics – www.dkphotonics.com  specializes in designing and manufacturing of high quality optical passive components mainly for telecommunication, fiber sensor and fiber laser applications,such as PLC Splitter, WDM, FWDM, CWDM, DWDM, OADM,Optical Circulator, Isolator, PM Circulator, PM Isolator, Fused Coupler, Fused WDM, Collimator, Optical Switch and Polarization Maintaining Components, Pump Combiner, High power isolator, Patch Cord and all kinds of connectors.

Introduction of FBG Filter Embedded Adaptor-FBG filters for live network monitoring using in FTTH

Introduction of FBG Filter Embedded Adaptor-FBG filters for live network monitoring using in FTTH

FBG Filter Embedded Adaptor

FBG Filter Embedded Connector

FBG filters for FTTx applications are reflective filters integrated in the LC or SC adapters, which reflect the 1625 nm wavelength and transmit all other (i.e. 1310, 1490 and 1550 nm). They can be used to monitor live network utilizing OTDR operating at 1625 or 1650 nm. End-to-end OTDR measurements from OLT to ONT are typically difficult due to the high point insertion loss introduced by the splitter and due to the required very good spatial resolution. The use of the 1625 nm reflectors is an efficient and cost-effective way of reducing the required dynamic range of the OTDR. The 1625 reflectors  are currently considered the best way of implementing  real time end-to-end (OLT to ONT) monitoring of the optical layer in live FTTx networks.

More information for the FBG Filter Embedded Connector

DK Photonics – www.dkphotonics.com  specializes in designing and manufacturing of high quality optical passive components mainly for telecommunication, fiber sensor and fiber laser applications,such as PLC Splitter, WDM, FWDM, CWDM, DWDM, OADM,Optical Circulator, Isolator, PM Circulator, PM Isolator, Fused Coupler, Fused WDM, Collimator, Optical Switch and Polarization Maintaining Components, Pump Combiner, High power isolator, Patch Cord and all kinds of connectors.

Application For Fiber Laser-Mainly Passive Optical Components in Fiber Lasers System_DK Photonics

Application For Fiber LaserMainly Passive Optical Components in Fiber Lasers System_DK Photonics

DK Photonics:Huawei to invest over $4 billion in fixed broadband technology in 3 years

Telecom network vendor Huawei on Thursday said it will be investing over $4 billion in fixed broadband (FBB) technology research and development over the next three years.

Huawei’s plans to invest significantly in fixed broadband technology reflects a report from Dell’Oro Group that said wireline telecom markets will grow at a CAGR of 3 percent against 1 percent growth for wireless between 2013 and 2018.

In August, Dell’Oro Group said the combined service provider equipment markets will grow at a CAGR of 2 percent between 2013 and 2018 — after recording a CAGR of -1 percent between 2008 and 2013.

Huawei said the $4 billion investment will focus on products and solutions which will support their customers with providing an improved service experience for end users.

Huawei Products and Solutions President Ryan Ding said: “Our investment will further develop technological advances, help customers increase their competitiveness and decrease overall operating costs.”

Existing technologies are changing, next-generation High-Efficiency Video Coding is maturing, 4k panel and content production costs are reducing and the development of the 4k video industry, are all driving new solutions.

As LTE and 5G deployment continues, construction of high-performance networks which guarantee better customer experience will be expected by telecom operators. Huawei said FBB technologies will be progressed by leveraging big data, data centers and cloud computing to meet their needs.

Tam Dell’Oro, president and founder of Dell’Oro Group, said: “While we believe carriers will continue to enhance their wireless networks, we anticipate carriers will put more emphasis on backhauling traffic which means improving their fixed line networks in the next five years.”

Huawei today said it will innovate Software Defined Networking (SDN), Network Functions Virtualization (NFV) to initiate open broadband networks that help customers simplify operations and management, realize service innovation and improve network efficiency.

For next-generation networks, Huawei will conduct research and develop on new key technologies and architectures for IP and all-optical networks, advancing FBB network development.

Fixed LTE broadband access gains

At present, 1.26 billion households do not have DSL, cable, or fiber-optic broadband. Fixed and mobile telecoms are looking to LTE to make the connection.

“By the end of 2014, there will be 14.5 million residential and commercial premises with fixed LTE broadband access. By 2019, that figure should grow to 123 million,” said Jake Saunders, VP and 4G practice director at ABI Research.

ITU pitches for broadband

ITU, a telecom industry association under the aegis of UN, says more than 40 percent of the world’s people are already online, with the number of Internet users rising from 2.3 billion in 2013 to 2.9 billion by the end of this year.

Over 2.3 billion people will access mobile broadband by end 2014, climbing steeply to a predicted 7.6 billion within the next five years.

ITU says there are now over three times as many mobile broadband connections as there are conventional fixed broadband subscriptions.

Huawei on green telecom

Meanwhile, Eric Xu, Rotating chief executive officer, Huawei, said: “Huawei is committed to socio-economic and environmental sustainability. We leverage our expertise to bridge the digital divide and deliver high-quality digital connectivity for all.”

“We always honor our commitment to supporting secure and stable network operations anytime, anywhere. We contribute to low-carbon economies by helping customers and industries improve productivity and reduce energy consumption,” said Xu at the sixth Global Supplier Sustainability Conference in Shenzhen, China.

DK Photonics – www.dkphotonics.com  specializes in designing and manufacturing of high quality optical passive components mainly for telecommunication, fiber sensor and fiber laser applications,such as PLC Splitter, WDM, FWDM, CWDM, DWDM, OADM,Optical Circulator, Isolator, PM Circulator, PM Isolator, Fused Coupler, Fused WDM, Collimator, Optical Switch and Polarization Maintaining Components, Pump Combiner, High power isolator, Patch Cord and all kinds of connectors.

Fiber Optics Sensors Provide Early Warning for Landslides-DK Photonics

CASERTA, Italy, Sept. 29, 2014 — Fiber optic sensors could warn people of imminent landslides, potentially saving lives and reducing destruction.

A team at the Second University of Naples is developing sensor technology that could detect and monitor both large landslides and slow slope movements. The researchers hope to mitigate the effects of these major natural disasters, similar to the way hurricane tracking can prompt coastal evacuations.

Optical fiber sensors embedded in shallow trenches within slopes would detect small shifts in the soil, the researchers said. Landslides are always preceded by various types of pre-failure strains, they said.

While the magnitude of pre-failure strains depends on the rock or soil involved — ranging from fractured rock debris and pyroclastic flows to fine-grained soils — they are measurable. Electrical sensors have long been used for monitoring landslides, but that type of sensor can be easily damaged, the researchers said. Optical fiber is more robust, economical and sensitive.

“Distributed optical fiber sensors can act as a ‘nervous system’ of slopes by measuring the tensile strain of the soil they’re embedded within,” said professor Dr. Luigi Zeni.

The researchers are also combining several types of optical fiber sensors into a plastic tube that twists and moves under the forces of the pre-failure strains. This will allow them to monitor the movement and bending of the optical fiber remotely to determine if a landslide is imminent.

The use of fiber optic sensors “allows us to overcome some limitations of traditional inclinometers, because fiber-based ones have no moving parts and can withstand larger soil deformations,” Zeni said.

He added that such sensors can be used to cover several square kilometers and monitored continuously to pinpoint critical zones.

The team will present their research at Frontiers in Optics in Tucson, Ariz., next month.

DK Photonics – www.dkphotonics.com  specializes in designing and manufacturing of high quality optical passive components mainly for telecommunication, fiber sensor and fiber laser applications,such as PLC Splitter, WDM, FWDM, CWDM, DWDM, OADM,Optical Circulator, Isolator, PM Circulator, PM Isolator, Fused Coupler, Fused WDM, Collimator, Optical Switch and Polarization Maintaining Components, Pump Combiner, High power isolator, Patch Cord and all kinds of connectors.